On Monday, August 21, 2017, a total solar eclipse will pass over the Pacific Northwest. The solar industry’s success in California means that the electric grid operators will have to plan for a period of time when the sky goes dark and solar generation plummets. While the generation loss is significant, it’s not the only problem. Grid operators also have to manage fluctuations in the “ramp rate,” which is a measure of change in solar generation coming onto the grid. The eclipse will cause solar generation to drop off by 70 megawatts per minute, then ramp back again up by 90 megawatts per minute. California Independent System Operator (CAISO) has a typical ramp rate of 29 megawatts per minute. This eclipse will put California’s grid operators to the test.

The yellow line in this chart shows the divergence in solar energy production that CAISO expects as a result of the solar eclipse on August 21.CAISO

Most people wouldn’t recognize the name, yet this organization is responsible for delivering 300 million megawatt-hours of electricity each year and managing about 80% of California's electric flow.

This nonprofit public benefit corporation grants access to transmission lines and coordinates diverse energy resources into the grid, where it is distributed to consumers. It also operates a competitive wholesale power market designed to promote a broad range of resources at lower prices.

Renewable resources increasingly satisfy the state’s electricity demand. But in many energy markets, the peak demand of electricity occurs after sunset, when solar power is no longer available. The amount of power needed to be generated quickly from sources beside solar or wind is huge, which is a major concern for grid operators. Storage can fix this problem by storing electricity when there is a lot of solar and demand is low, and releasing that energy back into the grid when there is peak demand. CAISO is looking to incorporating energy storage and distributed energy resources into their market.

I am working with the Market Design and Infrastructure Policy team. My main project is understanding how other ISOs are deciding how much renewables they are allowing into their markets. If we can understand how other ISOs are dealing with renewables, we may be able to learn from their success or challenges. I am also involved in the projects that are working to bring storage into the electricity market. I am excited to be an intern at CAISO where I will be performing energy and environmental policy research and help develop new market designs. In the future I would enjoy working with the electric grid to accommodate an increasing amount of renewable resources and to advance environmental goals.

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